Interface Guide¶
This page provides detailed reference for XdTd's interface elements, dialogs, and operations. For the conceptual overview, see Key Concepts.
Part 1 — Panel View Interaction¶
Most user interaction with a case study happens through the case study panel view and its toolbar. In the panel view, the mouse is used to navigate (wheel to zoom, click-and-drag on empty space to pan) and to select features — either a geometry feature (edge, vertex) or a complete component (boundary, crack, stiffener, patch). Once a feature is selected, the operations available for it are reached through context menus, opened with a right-click. Clicking on empty space clears the current selection.
The toolbar, described in Part 2, groups the operations that apply to the case study as a whole. Some toolbar buttons are also context-sensitive: they appear or disappear depending on what is currently selected (see Context-Sensitive Toolbar below).
Selection Model¶
XdTd uses two levels of selection:
Single click — selects individual edges and vertices. Click directly on or near the edge or vertex you want to select.
Double click — selects entire components. For boundaries and patches, double-click within the enclosed geometry. For stiffeners, double-click on or near the stiffener line.
The selection determines what operations are available through context menus.
For small features — such as short cracks — selecting them in the default (zoomed-out) panel view can be difficult, since the clickable area is too small relative to the cursor's hit tolerance. In these cases, zoom in (mouse wheel) until the feature is comfortably sized on screen, and the selection will be made without problems.
Context Menus¶
Right-click on a selected element to access its context menu. The available options depend on what is selected:
Edges and vertices:
- Boundary condition operations (create, change, delete)
- Edge splitting (at a point or into N segments)
- Edge crack definition
Components (boundaries, patches, stiffeners):
- Browse and change geometry
- Change material properties
- Change cross-section properties (stiffeners)
- Change attachment type (fastened or bonded, for patches and stiffeners)
- View results (when available)
External boundary has the richest context menu — from here you can also add internal boundaries, stiffeners, patches, and embedded cracks to the panel.
Selection scope for results. Most result types can be viewed both individually and for the whole panel. The selection at the moment you open the result determines which:
- Selecting a single component (a specific crack, stiffener, patch, etc.) and choosing a result type from its context menu opens the chart for that component only. For example, selecting one crack and asking for Stress Intensity Factors plots SIFs for that crack alone.
- Selecting the external boundary and choosing the same result type opens a chart that overlays the results for all components of that type on the panel — for example, SIFs for all cracks in a single chart. The same applies to stiffener and patch results.
Context-Sensitive Toolbar¶
The panel toolbar is not static. Some buttons are always visible (they apply to the case study as a whole), but others appear only when their target is selected:
- Selecting a component that supports clipboard operations (internal boundary, patch, stiffener, or crack) brings up Cut / Copy / Paste buttons in the toolbar.
- Operations performed through these context-sensitive buttons can be reversed with Undo / Redo, which appear in the toolbar when an action has been performed. Note that not all operations are reversible — Undo/Redo apply to clipboard and other reversible edits, but actions such as deleting a result set or running an analysis cannot be undone.
In short, the set of toolbar buttons visible at any moment reflects what you can do right now, given the current selection.
Clipboard¶
Internal boundaries, patches, stiffeners, and cracks can be cut, copied, and pasted (Ctrl+X, Ctrl+C, Ctrl+V). When a component of one of these types is selected, the corresponding Cut / Copy / Paste buttons also appear in the panel toolbar. When pasting, all properties (material, cross-section, attachment) carry over, but the geometry must be redefined for the new location.
Part 2 — Case Study Operations¶
Everything in this section is accessed through the panel view and saved to the case study (.xdtd file).
Panel Toolbar¶
The vertical toolbar on the right side of the panel window is organized into groups:
File & Export
- Weight and Cost — view weight and cost summary for the panel
- Save — save the case study (
Ctrl+S) - Export Picture — export the current panel view to an image file
View
- Reset View — reset pan/zoom to the default view
- Settings — open application settings
Clipboard
- Clear Clipboard — discard the clipboard contents
- Cut (
Ctrl+X) — cut selected component (removes from panel, stores in clipboard) - Copy (
Ctrl+C) — copy selected component to clipboard - Paste (
Ctrl+V) — paste from clipboard (geometry must be redefined) - Delete (
Del) — delete selected component
History
- Undo (
Ctrl+Z) — undo the last operation. Dropdown shows up to 10 recent actions. - Redo (
Ctrl+Shift+Z) — redo the last undone operation.
Mesh
- Generate Mesh — create the boundary element mesh
- Make Finer Mesh — regenerate with finer discretization
- Delete Mesh — remove the mesh (unlocks geometry for editing)
Analysis
- Run New BEM Analysis — configure parameters and run an analysis
- Delete Selected Results Sets — remove result sets from the case study
Comparison
- Compare Side by Side — compare result sets in separate charts
- Compare Mixing Results — overlay result sets in the same chart
These comparison buttons operate within the current case study. For cross-case-study comparison, see Part 4.
Panel Geometry¶
When creating a new panel, XdTd offers a range of predefined topologies:
| Topology | Description |
|---|---|
| Rectangle | Straight edges, suitable for basic stress analysis |
| Rounded Rectangle | Reduces stress concentrations at corners |
| Circle | Uniform stress distribution, no corner concentrations |
| Ellipse | Elongated structures or optimized weight designs |
| Triangle | Delta-shaped structures or corner regions |
| Trapezoid | Tapered structural components with parallel top and bottom edges |
| Regular Polygon | Multi-sided symmetric structures (pentagon, hexagon, etc.) |
| Slot | Structures with oblong holes or slotted connections |
| Semi-circular Cutout | Edge-notched or half-hole configurations for crack growth studies |
| Lug | Pin-loaded holes in mechanical joints |
| Test Specimen | Standard tensile test specimen configurations |
| T-shape / Cross / C-channel | Custom polygon templates opened in the geometry builder |
| Import | Arbitrary panel shapes from an external file |
The geometry dialog shows a live preview. Adjust parameters on the left, then click Update Graphic View to refresh. Use Restore to return to the initial values.
Context Menu Reference¶
Edge Operations¶
| Operation | Description |
|---|---|
| Split > At a Point | Split an edge at a parametric position |
| Split > N Times | Split an edge into N equal segments |
| Boundary Conditions > Create | Define a new BC on this edge for the active BC set |
| Boundary Conditions > Change | Modify the existing BC on this edge |
| Boundary Conditions > Delete | Remove the BC from this edge |
| Force Discretization | Control how loads are discretized along the edge |
| Results > Displacements | View displacement results along the edge |
| Results > Stresses | View stress results along the edge |
Vertex Operations¶
| Operation | Description |
|---|---|
| Boundary Conditions > Create/Change/Delete | Manage BCs at this vertex |
| Edge Crack > Add | Define an edge crack starting from this vertex |
| Edge Crack > Change Geometry | Modify an existing edge crack |
| Edge Crack > Delete | Remove the edge crack |
External Boundary Operations¶
| Operation | Description |
|---|---|
| Browse > Geometry | View the boundary geometry summary |
| Properties > Change Geometry | Modify the panel shape |
| Properties > Change Material Properties | Set sheet material and thickness |
| Boundary Conditions > All Edges/Vertices | Apply BCs globally |
| Add > Internal Boundary | Add a hole or cutout |
| Add > Embedded Crack | Add an internal crack |
| Add > Stiffener | Add a stiffener reinforcement |
| Add > Patch | Add a patch reinforcement |
| Results | Access all result visualizations (see Part 3) |
Internal Boundary Operations¶
| Operation | Description |
|---|---|
| Browse > Geometry | View the boundary geometry |
| Properties > Change Geometry | Modify the cutout shape |
| Boundary Conditions > All Edges/Vertices | Apply BCs to all edges/vertices |
| Results > Boundary Displacements/Stresses | View boundary results |
Stiffener Operations¶
| Operation | Description |
|---|---|
| Browse > Geometry / Attachment | View stiffener geometry or attachment details |
| Properties > Change Geometry | Modify position, orientation, length |
| Properties > Change Material Properties | Set stiffener material |
| Properties > Change Cross Section | Set cross-section (area, moment of inertia) |
| Properties > Attachment > Fastened | Switch to riveted/bolted connection |
| Properties > Attachment > Bonded | Switch to adhesive connection |
| Boundary Conditions | Set loads at stiffener end points |
| Results | Stiffener stresses, attachment stress-strain, deformation, residual strength |
Patch Operations¶
| Operation | Description |
|---|---|
| Properties > Change Geometry | Modify patch polygon |
| Properties > Change Material Properties | Set patch material |
| Properties > Attachment > Fastened | Switch to riveted/bolted connection |
| Properties > Attachment > Bonded | Switch to adhesive connection |
| Results | Patch displacements/stresses, attachment forces/deformation |
Crack Operations¶
| Operation | Description |
|---|---|
| Browse > Geometry | View crack geometry |
| Properties > Change Geometry | Modify crack length |
| Results > Stress Intensity Factors | View SIF values |
| Results > Residual Strength | View residual strength curves |
| Results > Crack Growth > Cycles | View cycles to failure |
| Results > Crack Growth > da/dN | View crack growth rate |
| Results > Crack Growth > Growth Path | View crack trajectory |
Material Properties Dialog¶
Set the sheet or reinforcement material properties. Properties can be loaded from the material database or entered manually.
Sheet Material Fields¶
| Field | Description |
|---|---|
| Description | Database code or user-defined name |
| Young's Modulus (E) | Stiffness in tension/compression — used in stress and displacement calculations |
| Poisson's Ratio (v) | Ratio of transverse to axial strain — typically 0.25 to 0.35 for metals |
| Shear Modulus (G) | Stiffness in shear — related to E and v by G = E / (2(1+v)) |
| Yield Strength (oy) | Stress at which plastic deformation begins — used in residual strength calculations |
| Ultimate Strength (ou) | Maximum stress before failure — critical for residual strength analysis |
| Ultimate Strain (eu) | Maximum strain at failure — used in strain-based failure criteria |
| Fracture Toughness (Kc/KIc) | Resistance to crack propagation — critical for residual strength determination |
| Thickness | Used for stress calculations and plane stress vs. plane strain conditions |
Crack Growth Parameters¶
| Field | Description |
|---|---|
| Crack Growth Formula | Crack growth law corresponding to the parameters below |
| Constant (C) | Multiplier in the da/dN equation — material-specific from fatigue testing |
| Exponent (m) | Stress intensity factor range exponent in Paris law: da/dN = C(DK)^m |
Reinforcement Material Fields¶
Same fields as sheet material, with the addition that higher stiffness provides better crack bridging and load transfer, and Poisson's ratio mismatch with the base material can create interfacial stresses.
Boundary Conditions Dialog¶
Edge Boundary Conditions¶
Each edge can have boundary conditions in two directions (X/tangential and Y/normal), with values at the start and end points allowing linear variation along the edge.
| Setting | Description |
|---|---|
| Application | Nodes (discrete points) or Elements (distributed along edge) |
| Reference Frame | Global (model X-Y axes) or Local (edge-aligned coordinates) |
| Type (X and Y) | None (free), Traction (applied force/stress), or Displacement (fixed/prescribed motion) |
| Start Value | BC value at edge start point — units depend on type |
| End Value | BC value at edge end point — allows linear variation |
Analysis Parameters Dialog¶
These parameters are configured when running a new analysis and are saved with the result set.
Crack Growth¶
| Setting | Description |
|---|---|
| Number of Increments | Number of crack growth increments to simulate |
| Increment Strategy | Multiple of crack tip element size, or user-defined length |
| Straight Crack Growth | Skip direction calculation if cracks are known to grow straight — saves computation |
| Same Growth Rate | Skip individual rate calculation if cracks grow at the same rate — saves computation |
| Stress Ratio | Stress ratio (R) for fatigue crack growth using Paris or Forman equation |
Attachment Behaviour¶
Choose how attachments respond during analysis: rigid, elastic, elastic but breaking at force limit, plastic, or plastic but breaking at deformation limit.
2D Analysis Case¶
Select the analysis type (plane stress or plane strain).
Part 3 — Results Exploration¶
Every chart window includes a results toolbar on its right side. This toolbar provides tools for exporting, importing, configuring, and comparing results.
Results Toolbar¶
View¶
- Reset View — reset the chart to its default zoom and position
- Change View Parameters — open the chart configuration dialog (see below)
Export¶
- Export Picture (graphical file) — save the chart as PNG, JPEG, or SVG
- Export Picture (HTML) — save as an interactive HTML file
- Export Data (CSV) — export the chart data to a CSV file
- Export Data (SQLite) — export the chart data to a SQLite database
- Save Config (.xdchart) — save the current chart configuration for later reuse
Import¶
- Import Data (CSV) — overlay reference data from a CSV file onto the current chart
- Load Config (.xdchart) — restore a previously saved chart configuration
Parameterization & Delta¶
- Create Parameterized Picture — generate a percentage-difference chart using one trace as the reference
- Create Delta Picture — generate an absolute-difference chart between two traces
Comparison (within current case study)¶
- Compare Results Sets Side-by-Side — open selected result sets in a grid layout
- Compare Results Sets Overlaid — overlay selected result sets in the same chart
These buttons are enabled only when two or more result sets are available.
Chart Configuration¶
The Change View Parameters button opens a configuration dialog specific to the current chart type. Common options include:
- Graph scaling — adjust chart size (50–100%)
- Show legend — toggle legend visibility
- Show bounding box — toggle axis box
- Show colorbar — toggle colorbar for contour plots
- Chart title — set or hide a custom title
- Axis ranges — set X, Y, and Z ranges manually
Additional data-specific parameters vary by visualization type (e.g., stage selection, component filtering).
Available Result Types¶
Sheet Results¶
- Boundary Stresses / Displacements — stress and displacement along boundaries
- Sheet Displacements — 2D and 3D views of the displacement field
- Sheet Stresses — 2D filled contour, line contour, scatter, or line plots; 3D scatter or surface
Crack Results¶
- Stress Intensity Factors (SIF) — K1, K2 values at crack tips
- Residual Strength — panel load capacity as a function of crack length
- Crack Growth — Cycles — crack length vs. number of fatigue cycles
- Crack Growth — da/dN — crack growth rate
- Crack Growth — Growth Path — spatial crack trajectory
Stiffener Results¶
- Stiffener Stresses — stress distribution along the stiffener
- Attachment Stress-Strain — chart, status by location, animation
- Attachment Deformation — deformation at each attachment point
- Attachment Forces/Stresses — force distribution at fastener/bond points
- Residual Strength — stiffener contribution to residual strength
Patch Results¶
- Patch Displacements / Stresses — 2D and 3D views
- Attachment Forces/Stresses — 3D scatter, 2D filled contour, 2D line
- Attachment Deformation — 3D scatter, 2D filled contour, 2D line
Part 4 — Results Comparison¶
XdTd provides two levels of results comparison, depending on whether you are comparing within a single case study or across multiple case studies.
Within a Case Study¶
From the panel toolbar or the results toolbar, click Compare Side by Side or Compare Mixing.
A dialog lets you select:
- Which result sets to compare (two or more required)
- Which component type (sheet, stiffeners, patches)
- Which component numbers (specific components or all)
- Which stages (specific crack growth stages or all)
- Which result type and graphical output
This is useful for comparing the effect of different analysis parameters, BC sets, or mesh refinements on the same geometry.
Across Case Studies¶
From the main window menu, select Compare Results > Side by Side or Compare Results > Mixing.
The same dialog appears, but now it shows result sets from all open case studies. This lets you compare results across different structural configurations — for example, comparing a panel with 5 stiffeners against one with 7 stiffeners, or different materials.
The available component types are filtered to the intersection of what exists across the selected case studies.
Cost and Weight Comparison¶
From the main window menu, select Compare Cost and Weight > Side by Side or Compare Cost and Weight > Mixing.
This is available when two or more case studies are open and allows direct comparison of the cost and weight of different design alternatives.
Part 5 — Global Settings¶
Settings are accessed via Application > Settings from the main window menu, or the Settings button on the panel toolbar. They are saved to ~/XdTd/_settings/XdTd2d_user_settings.json and apply globally — they are not saved to individual case studies.
The settings dialog is organized into five groups:
Analysis Parameters¶
Output Control¶
| Setting | Description |
|---|---|
| Formatted Output | Format for supplementary output files: None, Markdown, CSV, or Both |
Stress Intensity Factors¶
| Setting | Description |
|---|---|
| SIF Calculation Method | J-Integral or Crack Opening Displacement (CROD) |
Crack Propagation¶
| Setting | Description |
|---|---|
| Convergence Profile | Balance between accuracy and speed (1–5) |
Convergence profiles:
- Ultra-Precise — highest accuracy, most stable — for validation and publication
- Precise & Stable — high accuracy, strong stability — for difficult cases with oscillations
- Moderate — recommended default for production
- Loose & Fast — lower accuracy — for preliminary studies
- Very Loose — fastest — for quick feasibility checks
Attachment Line Residual Strength¶
| Setting | Description |
|---|---|
| Reference Points Per Side | Number of attachment points each side of the crack for residual strength calculation. Swift's recommendation: 15. Range: 10–20. Total reference count is 2x this value. |
Bonded Patches¶
| Setting | Description |
|---|---|
| Boundary Points as Attachment Points | When enabled, bonded patch boundary points are included as attachment points in the compatibility equations. Disabling uses only interior points, which may avoid over-constraining the solution near patch edges. |
Stiffeners¶
| Setting | Description |
|---|---|
| Auto-Relocate Reference Node | Automatically relocate stiffener reference nodes after the elastic analysis to maximize adherence to the Stress × Strain attachment behaviour. |
Fasteners Flexibility¶
| Setting | Description |
|---|---|
| Flexibility Formula | Empirical formula for fastener flexibility: Huth, Grumman, Douglas, or Direct |
Discretization Parameters¶
Internal Points¶
| Setting | Description |
|---|---|
| Create Internal Points | Automatically generate a grid of points inside the boundary for stress calculation |
Crack Elements¶
| Setting | Description |
|---|---|
| Adjacent Start Element Size Multiplier | Size of the first boundary element adjacent to a crack, as a percentage of the crack tip element size (0–100%) |
| Adjacent End Element Size Multiplier | Size of the last element in a segment, as a percentage of the start element size — creates a graded mesh (0–100%) |
Style Parameters¶
Application¶
| Setting | Description |
|---|---|
| Font Size | Application-wide font size (8–16) |
| Toolbar Button Size | Size of toolbar icon buttons (10–32) |
Charts¶
| Setting | Description |
|---|---|
| Title Font Size | Font size for chart titles (8–16) |
| Legend Font Size | Font size for chart legends (6–16) |
| Axis Labels Font Size | Font size for axis titles, e.g., "Stress [MPa]" (6–16) |
| Tick Labels Font Size | Font size for axis tick values and colorbar labels (6–16) |
| Heatmap Color Map | Default color map for heatmap visualizations: Viridis, Plasma, Cividis, Magma, Inferno, Blues, Reds, Greens, Oranges, Purples, RdBu, Coolwarm, PiYG |
Application Theme¶
| Setting | Description |
|---|---|
| Color Theme | System (Auto), Light (B&W), or Dark (B&W) |
| Custom Background | Override the theme background with a user-selected color |
File Paths Parameters¶
| Setting | Description |
|---|---|
| Design Database File | Path to a custom .dbs database file with material properties |
| User Directory | Default folder for saving and loading case study files |
Both settings are optional — when unchecked, the application uses built-in defaults.
Global Parameters¶
| Setting | Description |
|---|---|
| Logging Level | Verbosity of log messages: Debug (most verbose), Info, Warning, Error, Critical (least verbose) |
| Maximum Dimension | Characteristic length of the model in millimeters, used for scaling and numerical stability. All units must be consistent (mm). |
Reset to defaults
Use Application > Reset Settings to restore all settings to their default values.